Ok, I have had this problem since 2.2 was released. Every launcher I try is now insanely slow, especially when I exit an app. The launcher loads, but it takes forever for it to show the icons and widgets. The stock 2.2 launcher does it. Launcher Pro does it. ADW Launcher does it. The only launcher that comes reasonably close to a decent speed is Zeam, and even Zeam is slow. I rooted the phone and installed an overclocked 1Ghz kernel and it made no difference to the speed of the widgets and icons taking forever to refresh when a launcher loads.